I picked up my 2000 A6 6spd back in May with about 94,000 miles. Started using 93 octane, changed the oil with Mobil 1 5W-30, replaced the air filter, ran a fuel system cleaner through the tank to clean some carbon deposits off the fuel injector. Everything else on the car is in great shape including the turbos.

I've averaged 27.0 MPG over the last 3,000 miles, a combination of mostly local and some highway mileage. My commute to work and to my girlfriend's is littered with traffic lights in some areas and rural roads in others. I've gotten up to 29.2 or 30.4 MPG on a tank before.

For my typical point to point travels
- I take it easy before the engine temperature reaches 175°
- I keep my revs under 2,000 RPM when accelerating and I get into 6th gear before 40 MPH
- I constantly use my cruise control including DECEL and RES ACCEL buttons no matter how fast or slow i'm going
- I coast down declines
- I tail behind the biggest un-aerodynamic SUVs that get in front of me.



My questions:
1. What's the best mileage you get per tank

2. What viscosity synthetic oil are you using and in the summer/winter time, and what viscosity gets you to the optimal 175-200°F the fastest? I'm a Jersey driver by the way (one of the good kinds).

3. Is your gas mileage indicator ever inaccurate? Mine is reasonably close but I still rely on dividing the trip odometer reading by the fill-up amount.

4. Are there any drawbacks to using a typical STP fuel system cleaner everytime I change my oil? I'm convinced it makes a difference.

5. Is there anything I'm neglecting to do to help my mileage? (don't tell me to take off the base carrier bars)

 

The mileage you're getting is exceptional -- highest I've ever heard for combined driving (by FAR) across multiple forums.

I think you've probably topped out. I wouldn't expect to get more unless you get a grappling hook, some cable, and a cape. To your questions...

1) I've gotten as high as 24-25 but have dropped down to 21-22 (closer to 22) since the Ethanol blends kicked in (still running 93) and the AC use kicked in (try to use it minimally and do recirc to minimize compressor usage).

2) 0w40 may give you a bit better mileage and is also good for the turbos (although the main benefit of a lower initial number is how well the stuff flows when it's cold and you're already engaged in good warm-up practices).

3) I've been trusting the trip computer. One of these days I'll get around to double checking it. FYI, you CAN tune the computer if you find it's inaccurate using a VAG COM. Check Stoney's Links (see my sig) for details.

4) Don't know of any drawbacks with using STP. If you're getting that result, I may start!

5) Maintain proper tire pressure, minimize AC usage (thought don't open windows -- that will create additional drag), remove the roof rack (sorry, I couldn't resist).

 

I figured I was doing pretty well with 27.0 MPG. It's most attributable to using cruise control if you guys have never tried comparing the difference. I run the AC conservatively, keep the appropriate tire pressure, and my long leggy blonde is 115 lbs with unbelievable metabolism.

There are times when I think I should replace my full sized spare with a can of Fix-a-Flat. Bad idea?

And I've read for Quattro cars that tires should be rotated Front to Rear on the same side. How often do you guys rotate?


I think this is one of the most entertaining clips about gas mileage if you haven't seen this. Jeremy Clarkson takes an A8 4.0 TDI on an 800 mile trip from London to Edinburgh and back on a single tank (~19 gallons).

Top Gear - Audi A8 Challenge Part 1
Top Gear - Audi A8 Challenge Part 2

 

My friend, I honestly think that you've reached the ceiling for this car. Things like taking out the spare are, to my mind, going over the line (do you REALLY want that leggy friend of yours walking along a highway late some night because the can of fix-a-flat didn't do the job?).

Be happy with what you're getting (I think you'll find the people on AW will tell you that 27 is pretty exceptional - saw the post there as well) and enjoy the car. If you REALLY want better mileage, I'd suggest a hybrid or a scooter.

 

For what it's worth, when I bought my 2003 A6 2.7T 6-speed last year the original owner had run Mobil1 5W-40 and premium gas. I kept using the the oil but moved to midrange gas. My first few tanks were about 25mpg highway and have since dropped to @23mpg on mostly highway driving. I find several things influence mileage:
- cruising speed; definitely get better mpg at 60-65 rather than 75-80 (normal pack speed in Michigan)
- mpg is better when weather is warm/hot
- old lady shifting (under 2000 rpm same as you) and quickly upshifting
- pay attention to tire pressure, air filter, etc.

I watch the computer for the "instantaneous" reading but find it optimistic by at least 2 mpg for average. I keep a maintenance log for all my cars which includes miles driven divided by gallons filled to give a very accurate per tank average. So I'm not guessing - I can go back over the last 40K miles and figure it to the tenth of an mpg if I was so inspired.

I'm about to install a GIAC chip and I am quite curious if mpg will suffer. Since I generally shift just before or when the turbos are barely engaged, I'm hoping it will have minimal impact. But I suspect that having fun with the additional 60-70 hp will be reflected in lower mpg.

I think you're doing fantastic.

 

+1 i have a the 1.8T (2001.5) and i have found that with mobil1 and premium(i tried midgrade but found less mileage per tank) yields the best mileage. i too try to shift at low rpms(before the computer would shift) and like said above 60-70mph is a good crusing speed for the highway giving me the best mileage. Nice info PPGOAL

 

dude, why do you own a 2.7t?

i get anywhere from 19-21 avg, but there are a few key differences in our driving styles.

you keep your revs under 2000 while accelerating i rarely let mine drop below 2,800. you hit 40 in 6th, i hit it in 3rd, 4th if i'm driving mrs daisy or she's in front of me.

I only use cruise on the highway.

you coast down hills, i keep the motor engaged at all times unless changing gears, which i'll do downhill if i feel the need to.

you tail the biggest SUV to get in front of you, i pass them, and the people in front of them too.

you might get another 5-8 MPG, but i have a hell of a lot more fun driving mine than you do yours..

 

in most cases, the opposite is true. the extra hp produced means less throttle input required for the same performance metrics. less throttle means... ahh do i have to spell it out? most people see a lowered mpg after a performance mod because they are enjoying the new power and giving it more throttle than they would have prior... if you want to increase your mpg even more, open it up and let it breathe... CAI and aftermarket cat-back would make a marked improvement.

 

Dont get a CAI, it will not help you MPG, i will hurt it. Audi designed a great airbox, I modified my box with great rewards. CAI will end up drawing in alot of hot engine bay air. I put an AWE s flow on and lost 2mpg, put the stock box back in,then modded it and gained back my lost 2 plus 1 more. GIAC will net you better MPG as long as you dont have too much FUN. The fuel trim's are more aggressive, meaning they allow more air but trim back the fuel for a leaner burn. Obviously buring less fuel at a given speed will get you better MPG, why didn't AUdi tune this way, easy answer RICH S SAFE

 

Wow, old post resurrected. I did install the GIAC chip about 70k miles ago (currently at 143k). Car mileage did not change noticeably....still 23-24 mpg on the highway with recent highs this summer of 25.6 driving on cruise at 72 mph. I admit to accelerating conservatively most of the time, but I do romp on it when joining heavy traffic on the highway or passing. I frequently cruise at 75-80 and often hit 90-100 when passing/merging. You're right, it does not help the mpg but sure is fun. On the other hand, the gentle treatment has resulted in a high mileage car that is still OEM except for the alternator, clutch, and flywheel. Still running Mobil1 0W-40. Keep the tire pressure around 35-36.